Electrical protective device.



1 N. MAHONEY.

ELECTRICAL PROTECTIVE DEVICE.

APPLICATION FILED JULY H, I916. 137 Patented Dec. 17, 1918.

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UNITED STATES PATENT OFFICE.

JOSEPH N. MAHONEY, 0F WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTING-HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL-VANIA.

ELECTRICAL PROTECTIVE DEVICE.

Application filed July 11, 1916.

To all whom it may concern.

Be it known that I, J OSEPH N. MAHONEY, a citizen of the United States,and a resident of lVilkinsburg, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in ElectricalProtective Devices, of which the following is a specification.

My invention relates to electrical protective devices and particularlyto relay mechanisms that are employed for tripping cir cuit interruptersupon the occurrence of pre determined conditions.

One object of my invention is to provide a simple and economical relaysystem of the character indicated that may be operated by currentderived from the circuit in. connection with which the interrupter isemployed, thereby obviating the necessity of employing a separate sourceof energy for su splying the operating current for its trip col Anotherobject of my invention is to provide a system of the above indicatedcharacter that shall have a positive locking means for precluding theoperation of the tripping device until the relay has functionedproperly.

Copending application Serial No. 850,331, filed July 11, 1914 by B. H.Smith and assigned to the Westinghouse Electric and ManufacturingCompany, discloses a relay system that is adapted to supply a trip coilwith energy from the circuit in connection with which its interrupter isemployed. However, upon the occurrence of relatively high overloads, adevice of this type frequently permits the trip coil to operate itsmovable armature before the relay functions properly. In view of this, Iprovide a latch for positively locking the trip coil movable armature inits inoperative position until the relay operates.

The single figure of the accompanying drawing is a diagrammatic view ofa distributing system embodying my invention.

An electric circuit 1 is provided with an interrupter 2 having a tripcoil 3. The trip coil 3 is adapted to be supplied with energy through atransformer 4 and is adapted to be controlled, in its operation, byeither an overload or reverse-energy relay 5.

The relay 5 may be delayed or not in its time of operation and comprisesa mag netizable core member 6, windings and 8,

Specification of Letters Patent.

Patented Dec. 17, 1918. Serial No. 108,571.

an armature 9 and cooperating contact members 10 and 11. Anelectromagnet 12 comprises a stationary magnetizable core member 13, twowindings 14 and 15 and a pivotally-niounted armature 16 that is adaptedto be held in engagement with its stationary core member by the force ofgravity when the winding 14 is deenergized. The movable armature 18 ofthe trip coil 3 is provided with a beveled projection 19 that is adaptedto engage a similarly beveled projection 20 on the armature 16 for thepurpose of so looking the armature 18 as to preclude its operation untilthe relay 5 has operated to deenergize the electromagnet 12.

One terminal 4 of the transformer 4. is connected to one terminal of thewinding 8 of the relay 5, the other terminal of the winding 8 beingconnected to one terminal of the winding 14 of the electromagnet 12 andthe other terminal of the winding 14 being connected to one terminal ofthe winding 15 and to the terminal 3 of the trip coil 3. The otherterminal of the winding 15 is connected to the movable contact mem ber11 of the relay 5, and the terminal 3* of the trip coil 3 is connectedto the terminal 4 of the transformer 4. The stationary contact member 10is connected to the terminal 3 of the trip coil 3.

Under normal conditions, insufiicient current traverses the relay 5 tocause its armature to operate. However, sufficient current traverses thewinding 14 of the electromag net to hold the armature 16 in suchposition as to prevent the trip coil 3 from operating its armature 18.When an overload traverses the circuit 1, suflicient current traversesthe winding 8 of the relay 5 to eiiect engagement of the contact members10 and 11 and thus close the circuit of the winding 15. The current inthe winding 15 will induce a current in the winding 14 in opposition tothat which normally traverses it, whereby the core 13 will besubstantially demagnetized to permit such movement of the armature 16upon its pivot as to release the movable armature 18 of the trip coil 3to trip the circuit interrupter 2.

WVhen the interrupter 2 is tripped, no current traverses the windings 8and 14 and the trip coil 3, and, consequently, the contact members 10and 11 will be disengaged, and a spring 21 will move the armature 18 ofthe trip coil 3 to such position that the force of gravity will permitthe armature 16 to return to its initial position. Thus, when thewinding 14 is again energized, the projection 19 of the armature 18 willbe in such locked position that it will be permitted to operate onlyafter the relay 5 has functioned. The movement of the armature 16 is solimited by a stationary pin 17 that the projections 19 and 20 are notcompletely disengaged when the movable armature 18 is actuated. That is,the movement of the projection 19 forces the projection 20 downwardly asufiicient distance, that is limited by the pin 17, to permit it to tripthe interrupter 2 Without moving completely out of engagement. When thecircuit is openedand the spring 21 moves the armature 18 to its initialposition, the force of gravity will cause the armature 16 to assume theposition shown in the drawing. Thus, when the interrupter is againclosed, the device is in such position as to preclude the tripping ofthe interrupter until the relay operates.

I do not limit my invention to the structures illustrated, as it may bevariously modified without departing from the spirit and scope of theinvention, as set forth in the appended claims.

I claim as my invention;

1. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay operatively connected to thecircuit, and electro-magnetic means connected in circuit with the relayfor locking the trip coil armature in its inoperative position until therelay operates.

2. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay operatively connected to thecircuit and in series with the trip coil, and electro-magnetic meansconnected in circuit with the relay for locking the trip coil armaturein its inoperative position until the relay operates.

3. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay operatively connected to thecircuit and in series with the trip coil, and means connected in serieswith the relay and adapted to be controlled by the relay for locking thetrip coil armature in its inoperative position under predeterminedconditions.

4. In an electric circuit, the combination with a circuit interru terand a trip coil therefor, of a relay a apted to be supplied with currentfrom the circuit in accordance with the current traversing the circuit,and

means connected in series with the relay and the trip coil for lockingthe trip coil armature in its inoperative position under predeterminedconditions.

5. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay adapted to be supplied with currentfrom the circuit in accordance with the current traversing the circuit,and means connected in series with the relay and the trip coil forlocking the trip coil armature in its inoperative position until therelay operates. V

- 6. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay adapted to be supplied with currentfrom the circuit in accordance with the current traversing the circuit,and electro-responsive means connected in series with the relay andthetrip coil and adapted to be controlled by the relay for holding the tripcoil armature in a predetermined position until the relay operates,irrespective of the current traversing the same.

7. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a relay responsive to predeterminedconditions in the circuit, a latch for the trip coil armature, and anelectromagnet connected in series with the relay and the trip coil' fornormally holding the latch in such position as to prevent the operationof the trip coil armature until the relay 0perates.

8. In an electric circuit, the combination with a circuit interrupter, atrip coil therefor, and a series transformer operatively connected tothe circuit, of a relay, a latch for the trip coil armature, and anelectromagnet for controlling the latch having a winding that isconnected in series with the transformer, the relay and the trip coil,and a neutralizing winding that is adapted to be controlled by therelay.

9. In an electric circuit, the combination with a circuit interrupterand a trip coil therefor, of a transformer operatively connected to thecircuit, a relay connected in serice with the transformer and the tripcoil, and means controlled by the relay for locking the trip-coilarmature in its inoperative position under predetermined conditions. V

In testimony whereof, I have hereunto subscribed my name this 29th dayof June 1916.

JOSEPH N. MAHONEY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of iatents.

Washington, D. 0.

